Novel hydroxyaryl phosphine oxides, glycidyl ethers and epoxy compositions, composites and laminates derived therefrom

ABSTRACT

The invention provides new compositions of matter that are capable of forming cross-linked polymeric materials upon reaction with various known epoxy-containing compositions. Thus, the compositions of this invention are useful in the manufacturing of prepregs and laminates for PWB applications among many other uses. Preferred compositions of this invention include substituted hydroxyarylphosphine oxide mixtures, the glycidyl ether derivatives, or the epoxy resin oligomer adducts derived therefrom. The materials provide for laminates that have higher glass transition temperatures, improved thermal stability, and that are free of halogen.

CLAIM FOR PRIORITY

[0001] This application claims the benefit of the filing date of U.S.Provisional Patent Application Ser. No. 60/268,975, filed Feb. 15, 2001,entitled “Mixed Hydroxyphenyl Phosphine Oxides and Glycidyl Ethers andEpoxy Oligomers Derived Therefrom for Flame Retarding Printed WiringBoards”.

FIELD OF THE INVENTION

[0002] This invention relates to new compositions of matter, such ashydroxyarylphosphine oxide mixtures and derivatives thereof, which areusefull as flame retardants for epoxy resin compositions, as well as aprocess to prepare these mixtures. More particularly, though notexclusively, this invention relates to novel compositions of hydroxyaryland/or glycidoxyarylphosphine oxides, mixtures thereof, and epoxyoligomers and compositions derived therefrom, useful for forming avariety of curable compositions. The present invention is also directedto flame retardant epoxy resins used to prepare prepregs, laminates,particularly copper clad laminates useful in manufacturing electroniccomponents such as printed wiring boards without the use ofhalogen-containing compounds.

BACKGROUND OF THE INVENTION

[0003] Composite materials based on epoxy resins have been used in avariety of day-to-day applications for a long time and continue to haveconsiderable importance because of their versatility. A specific exampleof such an application includes but is not limited to electricallaminates used in printed circuit boards (printed wiring boards, PWB).The epoxy resins used therein have particularly gained popularitybecause of their ease of processibility. Those epoxy resins also featuregood mechanical and chemical properties, such as for example, toughnessand resistance to a variety of organic solvents and also display goodchemical and moisture resistance. These properties permit the epoxyresin materials to be adapted to diverse application purposes and allowthe materials sharing in the composite to be used advantageously.

[0004] Generally, the epoxy resins are readily processed into compositematerials for PWB applications via the manufacturing of prepregs(B-staging). For example, the substrate material, which is typically aninorganic or organic reinforcing agent in the form of fibers, fleece andfabric or textile materials, is impregnated with the resin. This may beaccomplished by coating the substrate with a resin solution in an easilyvaporizable or volatilizable solvent. The coating may be carried out bya variety of well-known techniques including rolling, dipping, spraying,and combinations thereof. The prepregs are then heated in an ovenchamber to remove solvent and to partially cure the resin. The prepregsobtained after this process must not self-adhere, but they also shouldnot be fully cured. In addition, the prepregs must be sufficientlystable in storage. In the subsequent processing into compositematerials, the prepregs must furthermore fuse when there is a rise intemperature and pressure and must bind together under pressure with thereinforcing agents or insertion components as well as with the materialsprovided for the composite as compactly and permanently as possible;that is the cross-linked epoxy resin matrix must form a high degree ofinterfacial adherence with the reinforcing agents, as well as with thematerials to be bonded together, such as metallic, ceramic, mineral andorganic materials.

[0005] A key requirement in many applications is the requirement forflame resistance. In many areas, this requirement is given firstpriority, due to the danger to human beings and material assets, forexample in structural materials for airplane and motor vehicleconstruction and for public transportation vehicles. In electrotechnicaland particularly electronic applications, it is absolutely necessary forthe electrical laminate materials to be flame resistant, due to thesubstantial worth of the electronic components assembled thereon and theintrinsic value of human life associated with working on or near devicescontaining PWB components.

[0006] Accordingly, it has been customary in the preparation ofepoxy-containing laminates to incorporate into the epoxy resincompositions various additives and/or reactives to improve the flameretardancy of the resulting laminate. Many types of flame retardantsubstances have been used, however, the most common thus far usedcommercially have been halogen containing compounds such astetrabromobisphenol A, prepared by reacting the diglycidyl ether ofbisphenol A with tetrabromobisphenol A. Typically, in order to reach thedesired fire retardancy level (V-0 in the standard “UnderwritersLaboratory” test method UL 94), levels of such bromine-containing flameretardant substances are required that provide a bromine content from 10weight percent to 25 weight percent based on the total weight in theproduct.

[0007] Generally, halogen-containing fire retardant epoxy resins such asthose containing tetrabromo-bisphenol A are considered to be safe andeffective. However, there has been increasing interest by some toutilize flame-retarded epoxy systems that are not based on halogenchemistry. It is desirable for these new materials to be able to meetthe requirements of fire retardancy and to display the same advantagesof mechanical properties, toughness, and solvent and moisture resistancethat is offered with the halogenated materials currently used.

[0008] One such approach proposed by many researchers has been the useof phosphorus based fire retardants. See for example, EP 0 384 939; EP 0384 940; EP 0 408 990; DE 4 308 185; DE 4 308 187; WO 96/07685; WO96/07686; U.S. Pat. No. 5,648,171; U.S. Pat. No. 5,587,243; U.S. Pat.No. 5,576,357; U.S. Pat. No. 5,458,978; and U.S. Pat. No. 5,376,453; allof which are incorporated herein by reference in their entirety. In allof these references, a formulation is formed from the reaction of aflame retardant derived from a phosphorus compound and an epoxy resin,which is then cured with an amino cross-linker such as dicyandiamide,sulfanilamide, or some other nitrogen element containing cross-linker toform the thermosetting polymer network.

[0009] Specific examples of commercially available phosphorus-based fireretardant additives include Antiblaze™ 1045 (Albright and Wilson Ltd,United Kingdom) which is a phosphonic acid ester. Phosphoric acid estershave also been used as additives, such as, for example, PX-200(Diahachi, Japan). Commercially available reactive phosphorus containingcompounds that have been disclosed as being suitable for epoxy resinsinclude Sanko HCA and Sanko HCA-HQ (Sanko Chemical Co., Ltd., Japan).

[0010] Alkyl and aryl substituted phosphonic acid esters areparticularly compatible with epoxy resins. More particularly, C₁-C₄alkyl esters of phosphonic acid are of value because they contain a highproportion of phosphorus, and are thus able to impart fire retardantproperties upon resins in which they are incorporated. However, thephosphonic acid esters are not satisfactory as a substitute forhalogenated flame retardants in epoxy resins for the production ofelectrical laminates for various reasons. First and foremost of thesereasons are the phosphonic acid esters often times impart undesirableproperties. For example, the phosphonic acid esters are knownplasticizers and thus the laminates formed therefrom tend to exhibitundesirable low glass transition temperatures (T_(g)). An additionaldrawback is that the use of phosphonic acid esters in amounts sufficientto provide the necessary flame retardancy increases the tendency of theresulting cured epoxy resin to absorb moisture. The moisture absorbencyof the cured laminate board is very significant, because laminatescontaining high levels of moisture tend to blister and fail, whenintroduced to a bath of liquid solder at temperatures around 260° C., atypical step in the manufacture of printed wiring boards.

[0011] Various other phosphorus based flame retardant materials aredescribed in the literature, which are either too expensive or featurecertain inferior properties. For example, EP 0 754 728 discloses acyclic phosphonate as a flame retardant material, which is incorporatedinto an epoxy resin. However, EP 0 754 728 indicates that this cyclicphosphonate should be present in large quantities, such as in excess of18 weight percent, in order for the resin system to meet UL 94 V-0. Thisloading for a phosphonate compound may lead to a depression of the Tg orhigher moisture absorption. EP 1 116 774 utilizes a hydrogenphosphinate, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, inconjunction with triphenylphosphine oxide. However, the epoxy resin baserequires the use of non-standard epoxy resins; namely a xylene-modifiednovolak resin and naphthylene aralkyl and biphenyl-modified epoxyresins. WO 99/00451 discloses another flame retardant compositionutilizing phosphonic acid esters. Although this composition appears toexhibit improved flame retardant properties at low levels of phosphonicacid ester, there is still a need in the industry for a flame retardantepoxy resin with improved T_(g) and flame retardant properties.Phosphorus flame retardant additives, in general, can lead to asignificant plastisizing effect (U.S. Pat. No. 5,587,243 and referencescited therein). Also, in the case of additive compounds, there may be aquestion of the additives leaching from a thermoset polymer networkunder processing conditions or over time.

[0012] Other methods to impart flame retardancy involve preparation ofhalogen-free flame retardant epoxy resin compositions using acombination of resinous materials and an inorganic filler, such asaluminum trihydrate (EP 0 795 570 A1) or magnesium hydroxide (JP2001213980 A2). These materials could potentially render the processingof the epoxy resins more difficult, as they are insoluble in the resinsystems. Additionally, fairly large load levels are usually required,which can detract from the properties. See, generally, U.S. Pat. No.6,097,100 and references cited therein for a description of variousinorganic fillers; and WO 01/42359.

[0013] Various other phosphorus compounds have also been used to preparehalogen-free flame retardant epoxy resins useful in the manufacture ofcomposite materials. For example, the use of phosphorus-carbon bondedmoieties, such as phosphine oxides, have been disclosed in WO 01/42253;U.S. Pat. No. 4,345,059; EP 1 116 774; and JP2000186186; all of whichare incorporated herein by reference in their entirety. A keydisadvantage of these compositions, however, is that they are costly toprepare, because they utilize unique raw materials. For example,JP2000186186 discloses the use of purebis(p-hydroxyphenyl)phenyl-phosphine oxide, which requires the use of apure dichlorophenyl phosphine. In an analogous manner, the phosphineoxides utilized in WO 01/42253 require lithium reagents and cryogenicreaction conditions, thus warranting special equipment for itsmanufacture. The phosphine oxides display benefits of improvedresistance to moisture uptake when compared with other phosphoruscompounds that contain P-O bonded moieties, as disclosed in WO 01/42253.

[0014] Thus, it is an object of this invention to provide economical yetuseful phosphine oxide compounds for the manufacture of non-halogenepoxy resins having utility in the manufacture of composite materials,such as electrical laminates for printed wiring boards or printedcircuit boards.

[0015] It is yet an other object of this invention to provide phosphineoxide containing, hydrolytically and thermally stable, non-halogenated,flame resistant epoxy resin compositions, which are used for makinglaminates for printed wiring boards and various other compositematerials.

[0016] Further, it is also an object of this invention to providephosphine oxide containing epoxy resin compositions having improvedflammability reductions when compared with bisphenol A based epoxylaminates.

[0017] Finally, it is an object of this invention to provide halogenfree phosphine oxide containing epoxy resin compositions that are usefulas replacements for tetrabromobisphenol A in FR-4 laminate applications.

[0018] These and other objects and advantages of the invention will beseen from the following detailed description.

SUMMARY OF THE INVENTION

[0019] The present invention is directed to novel mixtures ofhydroxyarylphosphine oxides, their use in epoxy compositions and methodsof producing them. There is thus provided in one aspect of the inventiona mixture of hydroxyarylphosphine oxides comprising:

[0020] (a) a mono(hydroxyaryl)phosphine oxide of the formula:

[0021] wherein R₁ is a divalent, substituted or unsubstituted arylenemoiety and R₂ is a monovalent substituted or unsubstituted aryl moietyor is an alkyl moiety or is an aralkyl moiety; and

[0022] (b) a bis(hydroxyaryl)phosphine oxide of the formula:

[0023] wherein R₁ and R₂ are defined as above; and

[0024] (c) a tris(hydroxyaryl)phosphine oxide of the formula:

[0025] wherein R₁ is defined as above; and

[0026] (d) optionally containing minor amounts of a pentavalentphosphine oxide of the formula:

[0027] wherein R₂ is defined as above. The present invention likewiseincludes the corresponding alkoxyaryl ether mixtures and theirderivatives where the hydroxyaryl moiety is replaced by a methoxyaryl,propoxyaryl, butoxyaryl or other C₁-C₆ (1 carbon to 6 carbon) alkoxyarylsubstitution on the phosphine oxide nucleus.

[0028] In yet another aspect of this invention mixtures of glycidylethers derived from a mixture of hydroxyarylphosphine oxides describedherein are provided.

[0029] Yet in another aspect of this invention novel curable flameretardant epoxy compositions derived from the novel hydroxyarylphosphine oxides or the glycidyl ethers of this invention are provided.

[0030] In another aspect of this invention novelbis(hydroxyphenyl)phosphine oxides of the Formula (V) and noveldiglycidyl ethers of the formula (VI) are provided.

[0031] Wherein n=0-100, preferably 0-20, most preferably 0-5; andwherein −R is selected from the group consisting of

[0032] including phenyl, in the case of compound VI.

[0033] In another aspect of this invention a triglycidyl ether of thefollowing formula is also provided.

[0034] In further aspects of this invention, a series of curable epoxycompositions comprising a combination of novel bis(hydroxyaryl)phosphineoxides of this invention, and novel reaction adducts of mono-, bis-,tris(hydroxyaryl)phosphine oxide mixtures with curable epoxy resins isprovided. The curable epoxy resins may include, for example, but are notlimited to, epoxy novolak type resins and/or diglycidyl ethers ofbisphenol A and bisphenol F. Additionally, mono-, bis,tris(glycidoxyaryl)phosphine oxide mixtures and novelbis(glycidoxyaryl)phosphine oxides of this invention are described,which can act as curable epoxy resins. Resin-impregnated compositescomprising the curable flame retardant epoxy compositions describedherein are additionally provided.

BRIEF DESCRIPTION OF DRAWINGS

[0035] The invention is described in detail below with reference to thedrawings wherein like numerals designate similar parts and the inventionis described in connection with numerous examples. In the drawings:

[0036]FIG. 1 is a perspective exploded schematic view showing aplurality of resin-impregnated glass cloth layers and a copper foillayer of the class used to make printed wiring boards; and

[0037]FIG. 2 is a schematic view in sectional elevation of aheat-pressed copper clad laminate of the class used to make printedwiring boards including a plurality of intermediate strata formed fromglass prepregs which have been heat-cured into a substantiallyintegrated structure generally inseparable into its constituent layers.

DETAILED DESCRIPTION OF THE INVENTION

[0038] As used herein, the term “arylene” refers to a divalent aromaticsubstituent radicals covalently bonded to the phosphorous atom by way ofan aromatic carbon including phenylene, biphenylene, naphthylene, andthe like; the term “aryl” refers to corresponding monovalent aromaticsubstituent radicals covalently bonded to the phosphorous atom by way ofan aromatic carbon including phenyl, biphenyl, naphthyl, and the like;substituted analogs thereof means said arylene moiety or aryl moiety issubstituted by at least one suitable substituent group selected from thegroup consisting of straight or branched alkoxy group such as methoxy,straight or branched alkyl and/or fluoroalkyl group such as methyl,trifluoromethyl, alkenyl group such as vinyl, and the like, providedthat such substituent does not interfere with the ability of thephosphorus compound to react with the epoxy resin. Thus, for example,when R₁ is phenylene, examples of suitable substituted R₁ are o, m orp-hydroxy-methyl-phenyl or commonly known as o-cresyl, m-cresyl,orp-cresyl; and so forth.

[0039] “Alkyl” means a straight chain, branched or cyclic saturatedsubstituent typically of 1-20 carbon atoms including methyl, ethyl,propyl substituents and so forth; whereas “aralkyl” and likesubstituents are characterized by bonding to the nucleus through asaturated carbon and including aromatic structures. Such substituentsinclude phenylpropyl or phenylbutyl substituents and so forth.

[0040] Thus in accordance with the practice of this invention there isprovided novel mixtures of hydroxyarylphosphine oxides, their use inepoxy compositions and methods of producing them. The curable epoxycompositions so formed are particularly useful in the manufacture oflaminates that are suitable in the production of printed circuit boardsor printed wiring boards.

[0041] There is thus provided in one aspect of the present invention amixture of hydroxyarylphosphine oxides comprising:

[0042] (a) a mono(hydroxyaryl)phosphine oxide of the formula:

[0043] wherein R₁, is a divalent, substituted or unsubstituted arylenemoiety and R₂ is a monovalent, substituted or unsubstituted aryl moietyor is an alkyl moiety or is an aralkyl moiety; and

[0044] (b) a bis(hydroxyaryl)phosphine oxide of the formula:

[0045] wherein R₁ and R₂are defined as above; and

[0046] (c) a tris(hydroxyaryl)phosphine oxide of the formula:

[0047] wherein R₁ is defined as above; and

[0048] (d) optionally containing minor amounts of a pentavalentphosphine oxide of the formula:

[0049] wherein R₂ is defined as above.

[0050] In one of the embodiments of this invention, R₁ in the aboveformulae is derived from an alkyl aryl ether. Examples of such startingmaterials include methoxyphenyl-, 4-methoxynaphthyl-, o-methoxycresyl-and so forth.

[0051] In another embodiment of this aspect of the invention, themixture is consisting essentially of diphenyl(4-hydroxyphenyl)phosphineoxide, bis(4-hydroxyphenyl)phenylphosphine oxide andtris(4-hydroxyphenyl)phosphine oxide, said mixture optionally includingminor amounts of triphenylphosphine oxide.

[0052] In a preferred embodiment of this invention, the mixturecomprises from about 10 to about 50 mole percent of themono(hydroxyaryl)phosphine oxide of the formula (1), from about 30 toabout 60 mole percent of the bis(hydroxyaryl)phosphine oxide of theformula (II), from about 10 to 50 mole percent of thetris(hydroxyaryl)phosphine oxide of the formula (III) and from about 0up to about 10 mole percent of the pentavalent phosphine oxide of theformula (IV).

[0053] In another aspect of this invention there is also provided amixture of glycidyl ethers derived from a mixture ofhydroxyarylphosphine oxides by way of reacting the mixture ofhydroxyarylphosphine oxides described herein with epichlorohydrin. Suchreactions can be carried out by any of the well-known techniques in theart. The molecular weights (or EEW) of the productglycidoxyarylphosphine oxide mixtures can be affected by varying thestoichiometry of the epichlorhydrin used in the reaction with themixture of hydroxyarylphosphine oxides described herein. Alternatively,the lower molecular weight glycidoxyarylphosphine oxide mixtures can beadvanced with the described hydroxyarylphosphine oxide mixtures of thisinvention to obtain a desired molecular weight or EEW.

[0054] A preferred method of making the mixture of hydroxyarylphosphineoxides includes (a) preparing a mixed Grignard reaction mixtureincluding the species (R₁)MgX and (R₂)MgX wherein R₁, is anarylalkylether radical and R₂ is an aryl or alkyl or aralkyl radical, Xrepresenting a halogen atom; (b) reacting the mixed Grignard reactionmixture with phosphorous oxychloride to produce a mixture ofarylalkyletherphosphine oxides; and (c) converting the mixture ofarylalkylether-phosphine oxides to the mixture of hydroxyarylphosphineoxides, noted above. A suitable method of converting the arylalkylethersto arylhydroxides involves treatment with HBr, HI or HCl in the presenceof a metal halide salt.

[0055] This invention utilizes, in a general sense, the use of a mixedGrignard reagent system to produce a mixture of phosphine oxides. Thisinvention can be applied to a wide array of compounds wherein anarylmagnesium halide can be mixed with an alkoxyarylmagnesiun halide andreacted with phosphorus oxychloride, or alternatively, an alkylmagnesiumhalide can be reacted with phosphorus oxychloride in tandem with analkoxyarylmagnesium halide. The generalized approach is to use a mainGrignard reagent that contains a functional group that can be chemicallytransformed to a group capable of reacting with a wide variety of activeintermediates, and furthermore, using a second Grignard reagent that isfunctionally inert. The relative stoichiometry between the two Grignardreagents and the phosphorus oxychloride can be adjusted to affect thedistribution of the mixtures in the desired fashion at will. The twoGrignard reagents can be premixed and reacted with the phosphorusoxychloride together, or the reagents can be added to the phosphorusoxychloride in a serial fashion, depending on the requirements of theparticular reaction. Alternatively, phosphorus trichloride can be usedin place of phosphorus oxychloride in the reaction, followed byoxidizing the resulting phosphine to phosphine oxide by standardsynthetic procedures.

[0056] Alternatively, a wide array of organometallic reagents andintermediates can be used to effect the product mixture distribution inplace of the magnesium approach. These reagents are, for example, butnot limited to: organozincs, -sodium, -lithium, -potassium, andtransition metal facilitated routes in general, which are known to oneskilled in the art.

[0057] The invention pertains, in a preferred aspect, to the substancesobtained by a two step process. The first step involves the reaction ofphosphorus oxychloride with a novel mixture of phenylmagnesium bromideand 4-methoxyphenylmagnesium bromide. The reaction produces a furthernovel mixture of four products; triphenylphosphine oxide,diphenyl(4-methoxyphenyl)phosphine oxide,di(4-methoxyphenyl)phenylphosphine oxide, andtri(4-methoxyphenyl)phosphine oxide. The preparation of these mixtureshas the added benefit of being much more economical to produce thanmaking the pure materials, which require more expensive reagents.Surprisingly, the amount of triphenylphosphine oxide produced in thereaction can be controlled by the Grignard reagent stoichiometric ratioto a near negligible level. This product mixture can then be reactedwith concentrated hydrobromic acid in the presence of a catalytic amountof a metal halide to produce the corresponding mixture of free phenols:triphenylphosphine oxide, diphenyl(4-hydroxyphenyl)phosphine oxide,di(4-hydroxyphenyl)phenylphosphine oxide, andtri(4-hydroxyphenyl)phosphine oxide. Additionally, the neutral materialcould be removed by washing techniques if so desired.

[0058] In addition, the unsubstituted phenyl group in the product, asdescribed above in the preferred aspect, for example, can be replaced bysubstituting bromobenzene with another aryl or alkyl halide. Examples ofaryl halides include, but are not limited to 1-bromonapthylene;2-bromonaphthylene; 4-bromotoluene; 4-bromophenoxybenzene; and5-bromo-1,2,4-trimethylbenzene. Examples of alkyl halides include, butare not limited to, methyl bromide and tert-butyl bromide. The reactivegroups for the final product mixture, in the most preferred case, wouldbe the epoxy group or hydroxyl group, which could then be made to reactwith epoxy resins as a reactive diluent in the co-cure or as apre-reacted intermediate, or as a curing agent directly. It isrecognized that other functional groups could also be used. This lowercost approach produces a distribution of products in the productmixture.

[0059] The product distribution in the mixtures also facilitatesgeneralized advancement in epoxy resins. Curable, flame retardant epoxyresins suitable for use in the manufacture of resin formulations,prepregs, and laminates can be prepared from the forwarding reaction ofthe stated mixture with a commercially available epoxy resin. Theproduct distribution enables certain physical characteristics to beeasily affected in the cured and uncured resin. The properties involvedare, for example, but not limited to, molecular weight, viscosity, glasstransition temperature, and gel point. The reasons for this are relatedto the number of aromatic hydroxyl groups present in each reactivespecies. Using a specific case as an example, thedi(4-hydroxyphenyl)phenylphosphine oxide reacts linearly with an epoxyresin in the normal fashion as in the commercially usedtetrabromobisphenol A. However, tri(4-hydroxyphenyl)phosphine oxide canreact with a bifunctional epoxy resin as a cross linking agent to give across linked thermoset. The presence ofdiphenyl-(4-hydroxyphenyl)phosphine oxide off sets this characteristicby acting as a chain termination agent. This product mixture reactsreadily with epoxide groups in standard epoxy resins without the need ofa catalyst, such as a phosphonium salt. This reaction occurs readily atelevated temperatures, in the range of 100 to 200° C. A wide range ofmolecular weights can be obtained in the copolymer product resins by useof the appropriate reaction stoichiometry.

[0060] Representative epoxy resins suitable for use in the presentinvention are presented in Epoxy Resins Chemistry and Technology, SecondEdition edited by Clayton A. May (Marcel Dekker, Inc. New York, 1988),Chemistry and Technology of Epoxy Resins edited by B. Ellis (BlackieAcademic & Professional, Glasgow, 1993), Handbook of Epoxy Resins by H.E. Lee and K. Neville (McGraw Hill, New York, 1967), and EP 1116774 A2.Suitable epoxy resins are, but not limited to, epoxy resins based onbisphenols and polyphenols, such as, bisphenol A, tetramethylbisphenolA, bisphenol F, bisphenol S, tetrakisphenylolethane, resorcinol,4,4′-biphenyl, dihydroxynaphthylene, and epoxy resins derived fromnovolaks, such as, phenol:formaldehyde novolak, cresol:fornaldehydenovolak, bisphenol A novolak, biphenyl-, toluene-, xylene, ormesitylene-modified phenol:formaldehyde novolak, aminotriazine novolakresins and heterocyclic epoxy resins derived from p-amino phenol andcyanuric acid. Additionally, aliphatic epoxy resins derived from1,4-butanediol, glycerol, and dicyclopentadiene skeletons, are suitable,for example. Many other suitable epoxy resin systems are available andwould also be recognized as being suitable by one skilled in the art.

[0061] It is generally advantageous to use an epoxy resin whichpossesses on average more than 1 and preferably at least 1.8, morepreferably at least 2 epoxy groups per molecule. In the broadest aspectof the invention, the epoxy resin may be any saturated or unsaturatedaliphatic, cycloaliphatic, aromatic or heterocyclic compound whichpossesses more than one 1,2-epoxy group. Examples of heterocyclic epoxycompounds are diglycidylhydantoin or triglycidyl isocyanurate (TGIC).

[0062] The epoxy resin is preferably one that has no lower alkylaliphatic substituents, for example the glycidyl ether of a phenolnovolak, or the glycidyl ether of bisphenol-F. Preferred epoxy resinsare epoxy novolak resins (sometimes referred to as epoxidized phenolicnovolak resins, a term which is intended to embrace both epoxy phenolnovolak resins and epoxy cresol novolak resins).

[0063] Epoxy novolak resins (including epoxy cresol novolak resins) arereadily commercially available, for example, under the trade namesD.E.N.™, Quatrex™, (Trademarks of the Dow Chemical Company), and Epon™(trademark of Resolution Performance Products). The materials ofcommerce generally comprise mixtures of various glycidoxyphenyl andmethyl-, ethyl- propyl- glycidoxyphenyl groups.

[0064] The arylalkyletherphosphine oxide mixtures or the correspondinghydroxyaryl-phosphine oxide mixtures of the present invention can beapplied for use as flame retardants for a vast array of thermosettingand thermoplastic resins, such as polycarbonates, polyesters, vinylesters, cyanate esters, polyamides, polyimides, polyurethanes, and manyothers; but more specifically, to the flame retardation of epoxy resinsas a general approach. In addition, the deprotection of alkylaryl ethersgenerates an alkyl halide, which is a value-added product.

[0065] These mixtures, containing hydroxy substituents, may be convertedto any number of functional groups by those skilled in the art, such as,but not limited to, ethers, carbonates, carbamates, and esters to modifythe properties of the materials to improve the compatibility in a givenresin system. In particular, these mixtures may be converted to thecorresponding glycidyl ether derivatives or the phenolic mixtures can beused directly as a cross-linking agent in epoxy resin formulations. Thehydroxyphenyl mixtures, which may be chemically converted into epoxyoligomers by reaction with commercially available epoxy resins orepichlorohydrin, or the glycidyl ether mixtures are intended for flameretardant printed wiring boards.

[0066] These mixtures, containing hydroxy substituents, can also beconverted to phosphorus-containing oligomers and polymers such as, butnot limited to polycarbonates, polyesters, polyurethanes, polyimides,and vinyl esters, which would also act as flame retardants.

[0067] Furthermore, the product mixture can also be converted to theglycidyl ether derivatives by reaction with epichlorohydrin and a baseas described above. The glycidyl ether derivatives can then also be usedas a co-reactive in epoxy resin formulations intended for flameretardation applications. This approach can lead to a significantlyhigher level of phosphorus in the resin system. Furthermore, theglycidyl ether phosphine oxide mixtures can be advanced with hydroxylphosphine oxides of this invention to make oligomers.

[0068] Alternative methods to obtain the glycidyl ethers are availableand could also be employed. For example, the hydroxyarylphosphine oxidemixture can be converted to the allyl ether by treatment with allylchloride, followed by oxidation of the resulting olefin to an epoxygroup by known synthetic methods.

[0069] The phosphine oxide mixture, or after being converted to theglycidyl ethers, or after being advanced to epoxy oligomers, can becured with standard hardeners such as a combination of dicyandiamide and2-methylimidazole. The phenolic mixtures act as hardeners themselves.Other phenolic hardeners include, but not limited to, phenolic resinsobtained from the reaction of phenols or alkyl-substituted phenols withformaldehyde, such as phenol novolaks, cresol novolaks, and resoles.Other hardeners include amines, anhydrides, and combinations involvingamines with Lewis acids. Amine hardeners include, but not limited to,alkyl amines, aryl amines, amides, biguanide derivatives, melamine andguanamine derivatives, methylene-dianiline, diaminodiphenylsulfone,imidazoles, ethylenediamine, diethylenetriamine, polyamides,polyamidoamines, imidazolines, polyetheramines, araliphatic amines,dicyandiamide, and m-phenylenediamine. Combinations ofnitrogen-containing catalyst with Lewis acids include the heterocyclicsecondary and tertiary amines and the Lewis acids including oxides andhydroxides of zinc, tin, silicon, aluminum, boron, and iron. Othercuring agents include carboxylic acids and anhydrides,amino-formaldehyde resins, and amine-boron complexes. Many types ofcuring agents that would be useful can be found in any basic epoxy resintext. In addition, the resins described in the present invention (seeExample 3a for a specific case) may be formulated with additionaladditives and fillers to affect cure rate, enhance flame retardancy, andincrease physical properties. The formulation in Example 6 is intendedto be used for the manufacture of prepregs and glass-reinforcedlaminates for the fabrication of printed wiring boards.

[0070] Typically, fillers and reinforcing agents include mica, talc,kaolin, bentonite, wollastonite, glass fiber, glass fabrics glass matt,milled glass fiber, glass beads (solid or hollow), silica, or siliconcarbide whiskers and so forth. Many of these materials are enumerated inthe Encyclopedia ofMaterials Science and Engineering, Vol. # 3, pp.1745-1759, MIT Press, Cambridge, Mass. (1986), the disclosure of whichis incorporated herein by reference. Combinations of fillers arepreferred in some embodiments; whereas in other embodiments, thereinforcing agent makes up most of the composite of the invention, as inthe case of glass fabric used in prepregs and laminates for printedwiring boards.

[0071] Additionally, the resin described in the present invention (seeExample 3a for a specific case) may be formulated with otherflame-retardant materials as co-additives with the compounds of thepresent invention to improve the performance. These co-FR materialscould be either inorganic or organic and can be reactive or additivebased compounds. Examples of inorganic additive type materials include,but not limited to, aluminum trihydrate (ATH), magnesium hydroxide,barium hydroxide, calcium carbonate, titanium dioxide, and silicondioxide. Examples of organic based additives or reactives include, butnot limited to, triphenyl phosphate, resorcinol bis(di-2,6-xylylphosphate), 9,10-dihydro-9-oxa- 10-phosphaphenanthrene-10-oxide,bisphenol A bis(diphenyl-phosphate), melamine, melamine phosphate,melamine borate and many others familiar to one skilled in the art.

[0072] The preparation of the mixtures of the present invention has theadded benefit of being much more economical to produce than making thepure materials from pure intermediates, which consequently, requiresmore expensive reagents. As in, for example, one method in thepreparation of bis(4-methoxyphenyl)phenylphosphine oxide, which couldentail the use of dichlorophenylphosphine oxide. The raw materials usedin this specific invention are based on the relatively inexpensivephosphorus oxychloride and organo halides. Alternatively, one couldutilize phosphorus trichloride in the same type of chemistry and oxidizethe resulting phosphines to phosphine oxides by known synthetic methods.

[0073] To demonstrate the flame retardant activity of these mixtures, aseries of laminates was prepared using various forms of the preferredinvention. A study was undertaken in order to observe the intrinsicproperties of the reactive phosphine oxide and its derivatives upon theresulting laminates when using a bisphenol A based epoxy resin withoutthe use of any additional additives other than a standard hardener andaccelerator (see Examples below, particularly, Example 7, Table 3).Significant improvements in the flame retardant properties are observedwith the compositions of this invention. In addition, improvedthermomechanical properties are attained, such as improved thermalstability and good glass transition temperatures of the resultinglaminates, while offering significant advantages in cost savings.

[0074] Thus in accordance with the practice of this invention aresin-impregnated composite comprising at least one of a filler orreinforcing agent and the curable composition as described herein isprovided, which is at least partially cured. For example, the glycidylethers and epoxy resins of the invention are advantageously used in thefabrication of prepregs and laminates used to make printed wiringboards. The resin prepared as described herein is mixed with one or morehardener(s) and optionally accelerator(s) and applied to a glass cloth,such as glass cloth layers 10, 12, 14 as shown in FIG. 1. Theresin-impregnated sheets or prepregs are then at least partially curedin an oven typically at 150° C.-200° C. for a few minutes; for example,from 1-5 minutes.

[0075] In order to prepare a laminate of the class used for printedwiring boards, a plurality of prepregs are stacked next to each other asshown in FIG. 2, wherein resin-impregnated layers 10-24 are shown. Oneach side of the stack there is provided a copper foil layer, such aslayers 26, 28. The stack, including cloth layers 10-24 and foil layers26, 28, is then pressed at elevated temperatures in a press for an houror more to produce a consolidated laminate 30. Laminate 30 thus includesa plurality of fused layers 10-24 of the resin-impregnated glass fabric.If so desired, more or fewer layers of prepregs or foil may be useddepending on the desired structure.

[0076] In another embodiment of this invention, there is also provided anovel bis(hydroxyphenyl)phosphine oxide of the formula:

[0077] wherein −R is selected from the group consisting of

[0078] Specific examples of di(4-hydroxyphenyl)(aryl oralkyl)bisphenols, as disclosed herein includedi(4-hydroxyphenyl)-α-naphthylphosphine oxide,di(4-hydroxyphenyl)-β-naphthylphosphine oxide,di(4-hydroxyphenyl)-tert-butylphosphine oxide,di(4-hydroxyphenyl)-2,4,5-trimethylphenylphosphine oxide,di(4-hydroxyphenyl)-4-phenoxyphenylphosphine oxide anddi(4-hydroxyphenyl)-p-tolylphosphine oxide.

[0079] In another aspect of this embodiment of the invention, thebisphenols as described herein can also be converted to thecorresponding bis-glycidyl ethers by way of reaction withepichlorohydrin in the presence of base as described hereinabove. Boththe bisphenols and their bis-glycidyl ethers are suitable in theformation of curable epoxy formulations as described herein, which arefurther employed in the formation of fire retardant laminates asdescribed herein.

[0080] This invention is further illustrated by the following examples,which are provided for illustration purposes and in no way limit thescope of the present invention.

EXAMPLES (General)

[0081] In the Examples that follow, the following abbreviations areused:

[0082] BHPPPOM bis(4-hydroxyphenyl)phenylphosphine oxide mixture

[0083] CDCl₃ deutero-chloroform

[0084] DICY dicyandiamide

[0085] d₆-DMSO d₆-dimethylsulfoxide

[0086] DSC differential scanning calorimetry

[0087] EEW epoxide equivalent weight

[0088] EPON 828 Resolution Performance Products;4,4′-isopropylidenediphenol polymer with 1-chloro-2,3-epoxypropane

[0089] FR flame retardant

[0090] GC gas chromatograph

[0091] LC liquid chromatograph

[0092] MeCN acetonitrile

[0093] MI 2-methylimidazole

[0094] MW molecular weight

[0095] NMR nuclear magnetic resonance spectroscopy, usually ofphosphorus, ³¹p

[0096] T-260 refers to a test method defined by the IPC (AssociationConnecting Electronics Industries) to determine the time to delaminationat 260 ° C. Test method No.2.4.24.1 is used.

[0097] PGME Dowanol PM (the chemical used is 1-methoxy-2-propanol)

[0098] POCl₃ phosphorus oxychloride

[0099] PWB printed wiring boards

[0100] rt room temperature

[0101] T_(g) glass transition temperature

[0102] TGA thermal gravimetric analysis

[0103] THF tetrahydrofuran

[0104] TPPO triphenylphosphine oxide

EXAMPLE 1 Pure Hydroxyarylphosphine Oxides

[0105] 1a. Bis(4-methoxyphenyl)phenylphosphine Oxide. A slurry ofmagnesium (133.7 g, 5.50 mol), tetrahydrofuran (988g), and1,2-dibromoethane (0.1 g, 0.5 mmol) was refluxed for 20 min. under ablanket of nitrogen. 4-Bromoanisole (1002 g, 5.357 mol) was added bydrop over 6 h at a rate to maintain 70° C. The reaction mixture washeated for an additional hour. Dichlorophenylphosphine oxide (479.4 g,2.459 mol) was added by drop to maintain a temperature of 35° C. over 5h. The reaction mixture was worked up to givebis(4-methoxyphenyl)phenylphosphine oxide (770.8 g, 93% yield) as aviscous amber oil. ³¹P NMR: (d₆-DMSO) δ 30.2 (s).

[0106] 1b. Bis(4-hydroxyphenyl)phenyl Phosphine Oxide.Bis(4-methoxyphenyl)phenyl phosphine oxide (1.77 g, 5.2 mmol) andhydrobromic acid (31.0 g, 48%, 0.18 mol) were stirred at 123° C. for 21h. The flask was fitted with a sodium sulfite scrubber for containmentof methyl bromide. The reaction mixture was worked up to give theproduct as a tan powder (1.0 g, 62% yield). ³¹P NMR: (d₆-DMSO) δ27.9(s).

[0107] 1c. Tris(4-methoxyphenyl)phosphine Oxide. A reaction flask undernitrogen containing magnesium turnings (223.9 g, 9.21 mol) and 1950 mLTHF was charged with 1 drop of 1,2-dibromoethane and heated to refluxfor 1 h. Heating was removed and p-bromoanisole (1683 g, 9.00 mol) wasadded dropwise at a rate to maintain reflux. After holding the reactionmixture overnight, POCl₃ (460.0 g, 3.00 mol) was added slowly over 2 hat 50-79° C. and the resulting mixture was held overnight at 50° C. Theproduct was isolated by aqueous workup to give 984.5 g oftris(4-methoxyphenyl)phosphine oxide (89.0% yield). Recrystallizedanalytical specimen (from ethyl acetate): mp 145.2° C. (DSC), lit.143-144° C. (J. Org. Chem. 1960, 25, 2001).

[0108] 1d. Tris(4-hydroxyphenyl)phosphine Oxide. A reaction flaskcontaining tris(4-methoxyphenyl)phosphine oxide (973.2 g) was chargedwith 48% aq HBr (2250 mL) and KBr (126.1 g). The flask was fitted with asodium sulfite scrubber for containment of methyl bromide. The reactionmixture was heated to reflux (114° C.) and maintained at reflux untilcomplete based on HPLC analysis. The product was worked up to give 558.5g of tris(4-hydroxyphenyl)phosphine oxide (³¹P NMR (d₆-DMSO): δ 27.6(s); ¹H NMR (d₆-DMSO): δ 10.9 (s,3H), 7.38 (m, 6H), 6.84 (m, 6H)).

[0109] Following the procedures as set out in Example 1a variousmethoxyaryl phosphine oxides of this invention are prepared employingthe starting materials as summarized below: 1e.Bis(4-methoxyphenyl)(i-naphthyl)phosphine oxide: Magnesium 1333 g, 5.50mol THF 988 g 1,2-dibromoethane 0.1 g, 0.5 mmol 4-Bromoanisole 1002 g,5.357 mol Dichloro(1-naphthyl)phosphine oxide (612.5 g, 2.5 mol) 1f.Bis(4-methoxyphenyl)(2-naphthyl)phosphine oxide: Magnesium 133.7 g, 5.50mol THF 988 g 1,2-dibromoethane 0.1 g, 0.5 mmol 4-Bromoanisole 1002 g,5.357 mol Dichloro(2-naphthyl)phosphine oxide (612.5 g, 2.5 mol) 1g.Bis(4-methoxyphenyl)(4-methylphenyl)phosphine oxide: Magnesium 133.7 g,5.50 mol THF 988 g 1,2-dibromoethane 0.1 g, 0.5 mmol 4-Bromoanisole 1002g, 5.357 mol Dichloro(4-methylphenyl)phosphine oxide (522.5 g, 2.5 mol)1h. Bis(4-methoxyphenyl)-2,4,5-trimethylphenyl- phosphine oxide:Magnesium 133.7 g, 5.50 mol THF 988 g 1,2-dibromoethane 0.1 g, 0.5 mmol4-Bromoanisole 1002 g, 5.357 molDichloro-(2,4,5-trimethylphenyl)phosphine oxide (592.7 g, 2.5 mol) 1i.Bis(4-methoxyphenyl)(4-phenoxyphenyl)phosphine oxide: Magnesium 133.7 g,5.50 mol THF 988 g 1,2-dibromoethane 0.1 g, 0.5 mmol 4-Bromoanisole 1002g, 5.357 mol Dichloro(4-phenoxyphenyl)phosphine oxide (677.7 g, 2.5 mol)1j. Bis(4-methoxyphenyl)-tert-butylphosphine oxide: Magnesium 133.7 g,5.50 mol THF 988 g 1,2-dibromoethane 0.1 g, 0.5 mmol 4-Bromoanisole 1002g, 5.357 mol Dichloro-tert-butylphosphine oxide(437.5 g, 2.5 mol)

[0110] Following the procedures as set out in Example 1b varioushydroxyaryl phosphine oxides of this invention are prepared employingthe starting materials as summarized below: 1l.Bis(4-hydroxyphenyl)(1-naphthyl)phosphine oxide:Bis(4-methoxyphenyl)(1-naphthyl)phosphine 2.42 g, 5.2 mmol oxideHydrobromic acid 31.0 g, 48%, 0.18 mol 1m.Bis(4-hydroxyphenyl)(2-naphthyl)phosphine oxide:Bis(4-methoxyphenyl)(2-naphthyl)phosphine 2.42 g, 5.2 mmol oxideHydrobromic acid 31.0 g, 48%, 0.18 mol 1n.Bis(4-hydroxyphenyl)(4-methylphenyl) phosphine oxide:Bis(4-methoxyphenyl)(4-methylphenyl)phosphine 1.8 g, 5.1 mmol oxideHydrobromic acid 31.0 g, 48%, 0.18 mol 1o.Bis(4-hydroxyphenyl)(2,4,5-trimethylphenyl) phosphine oxide:Bis(4-methoxyphenyl)(2,4,5-trimethylphenyl) 1.94 g, 5.1 mmol phosphineoxide Hydrobromic acid 31.0 g, 48%, 0.18 mol 1p.Bis(4-hydroxyphenyl)-tert-butylphenyl- phosphine oxide:Bis(4-methoxyphenyl)-tert-butylphenylphosphine 1.65 g, 5.2 mmol oxideHydrobromic acid 31.0 g, 48%, 0.18 mol

EXAMPLE 2 Dihydroxyarylphosphine Oxide Mixtures.

[0111] 2a. Bis(4-methoxyphenyl)phenylphosphine Oxide Mixture. Magnesium(1430 g, 58.8 mol), tetrahydrofuran (12 L), and 1,2-dibromoethane (2.2g, 0.012 mol) were stirred under nitrogen for 1 h. The mixture was thenheated to reflux and then the heating stopped. Bromobenzene (3000 g,19.1 mol) and 4-bromoanisole (7150 g, 38.2 mol) were added consecutivelyat a rate to maintain a slow reflux (67° C.) over a period of 4 h. Thereaction mixture was then held for a further 5 h at 70° C. Phosphorusoxychloride (2930 g, 19.1 mol) was added at a rate to maintain atemperature of 70° C. (5 h). The reaction was then held at 70° C. for afurther 5 h. The reaction mixture was quenched and worked up to give theproduct mixture (5772 g, 89%) as an amber colored oil. ³¹P NMR:(d₆-DMSO) δ 26.9 (s, 6%), 26.8 (s, 23%), 26.6 (s, 44%), 26.5 (s, 27%).GC (area%): triphenylphosphine oxide 3.8%,diphenyl(4-methoxyphenyl)phosphine oxide 21.5%,bis(4-methoxyphenyl)phenyl-phosphine oxide 40.6%, andtris(4-methoxyphenyl)phosphine oxide 25.7%.

[0112] 2b. Bis(4-hydroxyphenyl)phenylphosphine Oxide Mixture.Bis(4-methoxyphenyl)phenylphosphine oxide mixture (2359 g, 6.97 mol),hydrobromic acid (48%, 8344 g, 49.5 mol), and potassium bromide (243 g,2.04 mol) were stirred at 120° C. for 48 h. The flask was fitted with asodium sulfite scrubber for containment of methyl bromide. The loweraqueous layer was removed and the product layer was worked up to affordbis(4-hydroxyphenyl)phenylphosphine oxide mixture as a tan powder (1601g, 74%). m.p. (DSC): 93° C. ³¹P NMR (d₆-DMSO): δ 27.7 (s, 24.7%); 27.5(s, 47.7%); 27.4 (s, 25.4%); 27.2 (s, 2.2%).

[0113] The mixed Grignard reaction was performed using varyingstoichiometries of Grignard reagent (Table 1.). The product ratios weredetermined by use of ³¹P NMR. Entry 2 was discussed in example text.TABLE 1 Mixed Grignard Reaction Using different Reagent Ratios. PhMgBrMeOPhMgBr POCl₃ % Mol % from ³¹P NMR Entry Equiv. Equiv. Equiv. Yld.TPPO¹ Mono² Bis³ Tris⁴ 1 0.60 2.4 1 85 0 9.7 38.3 52.0 2 1.0 2.0 1 89 623 44 27 3 1.5 1.5 1 80 12.1 37.2 37.5 13.2

[0114] 2c. Bis(4-methoxyphenyl)(4-methylphenyl)phosphine Oxide Mixture.Magnesium (1430 g, 58.8 mol), tetrahydrofuran (12 L), and1,2-dibromoethane (2.2 g, 0.012 mol) were stirred under nitrogen for 1h. The mixture was then heated to reflux and the heating stopped. Amixture of 4-bromotoluene (3268 g, 19.1 mol) and 4-bromoanisole (7150 g,38.2 mol) was added at a rate to maintain a slow reflux (67° C.) over aperiod of 4 h. The reaction mixture was then held for a further 5 h at70° C. Phosphorus oxychloride (2930 g, 19.1 mol) was added at a rate tomaintain a temperature of 70° C. (5 h). The reaction was then held at70° C. for a further 5 h. The reaction mixture was then worked up togive the product mixture (5563.8 g, 83%) as an amber colored oil uponconcentration. ³¹P NMR: (d₆-DMSO) δ 27.3 (s), 27.1 (s), 26.9 (s), 26.9(s), 26.7 (s). GC(area %): tris(4-methylphenyl)phosphine oxide 3.8%,bis(4-methylphenyl)(4-methoxyphenyl)phosphine oxide 21.0%,bis(4-methoxy-phenyl)(4-methylphenyl)phosphine oxide 39.4%, andtris(4-methoxyphenyl)-phosphine oxide 25.1%.

[0115] 2d. Bis(4-hydroxyphenyl)(4-methylphenyl)phosphine Oxide Mixture.A mixture of bis(4-methoxyphenyl)(4-methylphenyl)phosphine oxide mixture(470.2 g, 1.33 mol), hydrobromic acid (1458.1 g, 48%, 8.65 mol), andpotassium bromide (45.0 g, 0.378 mol) were stirred for 112 h at 110° C.The flask was fitted with a sodium sulfite scrubber for containment ofmethyl bromide. The lower aqueous layer was removed and the moltenproduct layer was worked up to givebis(4-hydroxyphenyl)-(4-methylphenyl)phosphine oxide mixture as a tanpowder (292.8 g, 77% yield). m.p. (DSC): 142.5° C. ³¹P NMR (d₆-DMSO):28.33 (s, 90.1%), 28.14 (s, 9.86%). LC(area%, THF:MeCN:water, 5:15:30):16.2, 48.9, 20.1.

[0116] 2e. Bis(4-methoxyphenyl)-2,4,5-trimethylphenylphosphine oxidemixture. A reaction flask under nitrogen containing magnesium turnings(120 g, 4.94 mol) and 412 mL THF was charged with 0.5 g of1,2-dibromoethane and heated to reflux for 1 h. A separate flask wascharged with 5-bromo-1,2,4-trimethylbenzene (300 g, 1.51 mol), dissolvedin 568 mL of THF. The heat was removed from the first flask and the5-bromo-1,2,4-trimethylbenzene solution was added dropwise at a rate tomaintain reflux. 4-Bromoanisole (536.7 g, 3.01 mol) was then added over1.5 h at 75° C. reaction temperature. After holding the reaction mixtureovernight, POCl₃ (231 g, 1.51 mol) was added dropwise at 40-80 ° C. Theproduct mixture was isolated by aqueous workup to give 453.6 g (79%yield) of product mixture as a viscous liquid. The structure wasconsistent with NMR data.

[0117] 2f. Bis(4-hydroxyphenyl)-2,4,5-trimethylphenylphosphine OxideMixture. A reaction flask containing thebis(4-methoxyphenyl)-2,4,5-trimethylphenylphosphine oxide mixture (443.7g) was charged with 48% aq. HBr (934 mL) and KBr (59.5 g). The flask wasfitted with a sodium sulfite scrubber for containment of methyl bromide.The reaction mixture was heated to reflux (118° C.) and maintained atreflux until complete based on HPLC analysis. The molten product wasworked up to give 283.3 g ofbis(4-hydroxyphenyl)-2,4,5-trimethylphenylphosphine oxide mixture as acream solid (68.9% yield). The ratio of products in the mixture based on³¹P NMR was 39% tris(4-hydroxyphenyl)phosphine oxide, 49%bis(4-hydroxyphenyl)-2,4,5-trimethylphenylphosphine oxide, 11%di-2,4,5-trimethylphenyl-4-hydroxyphenylphosphine oxide, and 1%tris(2,4,5-trimethylphenyl)phosphine oxide.

[0118] 2g. Bis(4-methoxyphenyl)(1-naphthyl)phosphine Oxide Mixture. Amixture of magnesium (125.2 g, 5.15 mol), 1,2-dibromoethane (0.1 g, 0.5mmol) and dry THF (1 L) were stirred under a blanket of nitrogen at rtfor 1 h. The mixture was brought to 65° C. and 1-bromonaphthalene (343.7g, 1.66 mol) was added by drop. Once the reaction initiated, the heatingwas removed and the 1-bromonaphthalene addition was continued for 2 h ata rate to maintain 55° C. 4-Bromoanisole (623.5g, 3.33 mol) was thenadded over 4 h. The temperature was adjusted to 65° C. and held for afurther 3 h. Phosphorus oxychloride (255.5 g, 1.66 mol) was then addedby drop to maintain a temperature of 50-60° C. over 6 hours. Thetemperature was then adjusted to 50° C. and held overnight. The reactionmixture worked up to afford bis(4-methoxy-phenyl)(1-naphthyl)phosphineoxide mixture as an amber solid (508 g, 79 yield %). ³¹P NMR (CDCl₃): δ37.49 (s, 3.0%), 35.32 (s, 2.4%), 33.64 (s, 31.1%), 30.37 (s, 50.8%),19.59 (s, 12.7%).

[0119] 2h. Bis(4-hydroxyphenyl)(1-naphthyl)phosphine Oxide Mixture.Bis(4-methoxyphenyl)(l-naphthyl)phosphine oxide (352 g, 0.906 mol),hydrobromic acid (1474 g, 48%, 8.74 mol), and potassium bromide (45 g,0.378 mol) were heated at 110° C. for 96 h. The flask was fitted with asodium sulfite scrubber for containment of methyl bromide. The mixturewas worked up to give the product as a brown solid (267 g, 82% yield).³¹P NMR (d₆-DMSO): δ 35.19 (s, 5.2%), 30.96 (s, 74.4%), 27.16 (s,19.3%). m.p. (DSC): 114.7° C.

[0120] 2i. Bis(4-methoxyphenyl)-tert-butylphosphine Oxide Mixture.Magnesium (30.1, 1.24 mol), tetrahydrofuran (400 mL), and1,2-dibromoethane (1 drop) were stirred under nitrogen for 1 h. Themixture was then heated to reflux and the heating stopped.4-Bromoanisole (224.4 g, 1.20 mol) was added as a mixture at a rate tomaintain a slow reflux (67° C.) over a period of 4 h. The reactionmixture was then held for a further 3 h at 70° C. To a tetrahydrofuran(500 mL) solution of phosphorus oxychloride (92.0g, 0.60 mol) was addedby drop tert-butylmagnesium chloride (300 mL, 2.0 M, 0.60 mole) over 5.5h and held at 40° C. for 1 h. Then the 4-methoxyphenylmagnesium bromidesolution prepared above was added by drop over 2 h at a rate to maintain40° C. The mixture was allowed to stir for 2 days at rt. The reactionmixture was worked up to yield a pale-yellow sticky solid (135.6 g,71%). ³¹p NMR (d₆-DMSO): δ 44.7 (s, 43.0%), 37.8 (s, 7.0%), 26.5 (s,7.6%), 25.4 (s, 36.4%), 14.9 (s, 6.0%).

[0121] 2j. Bis(4-hydroxyphenyl)-tert-butylphosphine Oxide Mixture.Bis(4-methoxyphenyl)-tert-butylphosphine oxide mixture (25.0 g),hydrobromic acid (770 g, 48%), and potassium bromide (30.0 g) werestirred for 25 h at 120 ° C. The flask was fitted with a sodium sulfitescrubber for containment of methyl bromide. The reaction mixture wasworked up to give a tan solid (9.6 g, 40%). ³¹P NMR (d₆-DMSO): δ 46.3(s, 31.8%), 39.6 (s, 31.7%), 28.7 (s, 20.4%), -8.2 (s, 16.1%).

EXAMPLE 3 Forwarding Reactions Using Hydroxyarylphosphine Oxides.

[0122] 3a. Bis(4-hydroxyphenyl)phenylphosphine Oxide Mixture/EPON 828Adduct. Bis(4-hydroxyphenyl)phenylphosphine oxide mixture (BHPPPOM) (329g) and EPON 828 (1318 g) were heated at 170° C. for 40 min.1-Methoxy-2-propanol (410 g) was then added to afford an amber coloredresin. Solution EEW: 460.9.% Solids: 86.

[0123] This procedure was repeated with different reactantstoichiometries to affect the final oligomer molecular weight andphosphorus content as shown in Table 2. TABLE 2 Forwarding Reaction ofEPON 828 with Bis(hydroxyphenyl)phenylphosphine oxide Mixture (BHPPPOM).Calc. Calc. BHPPPOM EPON 828 PGME % Solids EEW % P^(a) MW^(b) 80.4 g616.6 g 174 g 80.0 257.9 1 412.6 329 g 1218 g 410 g 86.0 460.9 2 792.8210.0 g 452.4 g 166 g 84.0 891.0 3 1496

[0124] 3b. Bis(4-hydroxyphenyl)(4-methylphenyl)phosphine OxideMixture/EPON 828 Adduct. Bis(4-hydroxyphenyl)(4-methylphenyl)phosphineoxide mixture (100 g) and EPON 828 (350 g) were heated at 170° C. for 90min. 1-Methoxy-2-propanol (PGME) (112 g) was then added to afford anamber colored resin. Solution EEW: 463.2.%Solids: 81.

[0125] 3c. Bis(4-hydroxyphenyl)phenylphosphine Oxide/EPON 828 Adduct.Bis(4-hydroxyphenyl)phenylphosphine oxide (196.0 g) and EPON 828 (782.0g) were heated at 170° C. for 40 min. The clear dark brown resin wasthen diluted with 218 g of PGME and filtered hot through a pad of glasswool. Solution EEW: 454;%Solids: 88.7.

[0126] 3d. Bis(4-hydroxyphenyl)phenylphosphine Oxide Mixture Enriched inTris(4-hydroxyphenyl)phosphine Oxide/EPON 828 Adduct. A mixture of EPON828 (330.9 g) and a sample of the bis(4-hydroxyphenyl)phenylphosphineoxide mixture assaying to contain triphenylphosphine oxide (3.0 g),diphenyl(4-hydroxyphenyl)-phosphine oxide (13.7 g),bis(4-hydroxyphenyl)phenylphosphine oxide (30.7 g) andtris(4-hydroxyphenyl)phosphine oxide (49.2 g) were heated at 170° C. for40 min. PGME (140 g) was then added to give a brown resin. Solution EEW:521.%Solids: 88.

[0127] 3e. Bis(4-Hydroxyphenyl)phenylphosphine Oxide Mixture Enriched inDiphenyl(4-hydroxyphenyl)phosphine Oxide/EPON 828 Adduct. A mixture ofEPON 828 (352.9 g), bis(4-hydroxyphenyl)phenylphosphine oxide mixtureassaying to contain triphenylphosphine oxide (3.0 g),diphenyl(4-hydroxyphenyl)phosphine oxide (39.2 g),bis(4-hydroxyphenyl)phenylphosphine oxide (30.7 g) andtris(4-hydroxyphenyl)phosphine oxide (19.2 g) was heated at 170° C. for40 min. PGME (111 g) was then added to give a brown resin. Solution EEW:396. %Solids: 83.8.

[0128] 3f. Tris(4-hydroxyphenyl)phosphine Oxide/EPON 828 Adduct. Amixture of tris(4-hydroxyphenyl)phosphine oxide (prepared in a methodanalogous to example 2a,b using three equivalents of bromoanisole) (21.2g) with EPON 828 (79.3 g) was heated over a 7 min period to 150° C. Themixture to this point was a slurry of the phosphine oxide in EPON 828.In the next 4 min., the pot reached a temperature of 180° C., and thispoint a portion of the phosphine oxide aggregated into a polymeric mass.

[0129] Following the procedures as set out in Example 3a, various epoxyresins of this invention are prepared employing the purehydroxyarylphosphine oxides as prepared in accordance with Example 1 orthe dihydroxyarylphosphine oxide mixtures as prepared in accordance withExample 2 and utilizing various epoxy resins known in the art. Arepresentative list of hydroxyarylphosphine oxides and the epoxy resinsthat can be employed are summarized below: Hydroxyarylphosphine oxidesEpoxy Resins Bis(4-hydroxyphenyl)phenylphosphine EPON 828 OxideTris(4-hydroxyphenyl)phosphine oxide D.E.N. ™Bis(4-hydroxyphenyl)(2-naphthyl) Quatrex ™ phosphine Oxide Phenolnovolaks Bis(4-hydroxyphenyl)(1-naphthyl) Glycidyl ether of bisphenol-Fphosphine Oxide Epoxy phenol novolak resinsBis(4-hydroxyphenyl)(4-methylphenyl) Epoxy cresol novolak resinsphosphine Oxide Bis(4-hydroxyphenyl)(2,4,5-trimethyl- phenyl)phosphineOxide Bis(4-hydroxyphenyl)tert-butylphenyl- phosphine OxideBis(4-hydroxyphenyl)phenylphosphine Oxide MixtureBis(4-hydroxyphenyl)(4-methylphenyl) phosphine Oxide MixtureBis(4-hydroxyphenyl)-2,4,5-trimethyl- phenylphosphine Oxide MixtureBis(4-hydroxyphenyl)(1-naphthyl) phosphine Oxide MixtureBis(4-hydroxyphenyl)-tert-butylphosphine Oxide Mixture

EXAMPLE 4 Glycidyl Ether Derivatives

[0130] 4a. Bis(4-glycidoxyphenyl)phenylphosphine Oxide Mixture.Bis(4-hydroxyphenyl)phenylphosphine oxide mixture (962.0 g, 3.10 mol),epichlorohydrin (2052.0 g, 22.18 mol), and methyl cellosolve (100 g)were heated to 80° C. Solid sodium hydroxide (260.4 g, 6.51) was addedslowly over 1.5 h. Towards the end of the addition, the exothermicreaction was cooled in an ice-bath. The volatiles were then strippedunder vacuum to a temperature of 160° C. Then methylene chloride (3 L)was added and the sodium chloride was removed by filtration. Afterfiltration, the volatiles were removed under vacuum at 150° C., and PGME(258 g) was added to give an amber resin. Solution EEW: 407.0. %Solids:88.

[0131] 4b. Tris(2-glycidoxyphenyl) phosphine Oxide. Heat a mixture oftris(2-hydroxyphenyl)phosphine oxide (198.2 g, 0.607 mol),epichlorohydrin (674.0 g, 7.28 mol), and methyl cellosolve (75 g) to 80°C. Add solid sodium hydroxide (76.4 g, 1.91) slowly over 1.5 h. Moderatethe reaction exotherm by cooling the reaction mixture in an ice-bath.Remove the volatiles under vacuum at a temperature of 160° C. Then addmethylene chloride (3 L) and remove sodium chloride by filtration. Afterfiltration, remove the volatiles under vacuum at 150° C. and isolate thetitle compound.

[0132] Following the procedures as set out in Example 4a variousglycidoxyaryl phosphine oxides and mixtures are prepared employing thepure hydroxyarylphosphine oxides as prepared in accordance with Example1 or the dihydroxyarylphosphine oxide mixtures as prepared in accordancewith Example 2, the glycidyl ethers thus prepared are summarized below:

[0133] Bis(4-glycidoxyphenyl)phenylphosphine Oxide

[0134] Tris(4-glycidoxyphenyl)phosphine Oxide

[0135] Bis(4-glycidoxyphenyl)(2-naphthyl)phosphine Oxide

[0136] Bis(4-glycidoxyphenyl)(1-naphthyl)phosphine Oxide

[0137] Bis(4-glycidoxyphenyl)(4-methylphenyl)phosphine Oxide

[0138] Bis(4-glycidoxyphenyl)(2,4,5-trimethylphenyl)phosphine Oxide

[0139] Bis(4-glycidoxyphenyl)-tert-butylphenylphosphine Oxide

[0140] Bis(4-glycidoxyphenyl)phenylphosphine Oxide Mixture

[0141] Bis(4-glycidoxyphenyl)(4-methylphenyl)phosphine Oxide Mixture

[0142] Bis(4-glycidoxyphenyl)-2,4,5-trimethylphenylphosphine OxideMixture

[0143] Bis(4-glycidoxyphenyl)(1- nap hthyl) phosphine Oxide Mixture

[0144] Bis(4-glycidoxyphenyl)(2-naphthyl)phosphine Oxide Mixture

[0145] Bis(4-glycidoxyphenyl)-tert-butylphosphine Oxide Mixture

EXAMPLE 5 Glycidyl Ether Derivative and Forwarding

[0146] Bis(4-glycidoxyphenyl)phenylphosphine OxideMixture/Bis(4-hydroxyphenyl)phenylphosphine Oxide Mixture Adduct.Bis(4-hydroxyphenyl)phenylphosphine oxide mixture (120 g, 0.387 mol),epichlorohydrin (256 g, 2.77 mol), and methyl cellosolve (13 g) wereheated to 80° C. Solid sodium hydroxide (32.6 g, 0.815 mol) was addedslowly over an hour and a half. Towards the end of the addition, thereaction exothermed and had to be cooled in an ice-bath. Then 500 mL ofmethylene chloride was added and the sodium chloride was removed byfiltration. The organics were stripped under vacuum to 150° C.Bis(4-hydroxyphenyl)phenylphosphine oxide (25.8 g, 0.0831 mol) was thenadded and held at 180° C. for 30 min. The resin was then diluted with 56g of PGME. Solution EEW: 610. %Solids: 83.

[0147] Following the procedures as set out in Example 5 variousglycidoxyaryl phosphine oxides and mixtures are prepared employing thepure hydroxyarylphosphine oxides as prepared in accordance with Example1 or the dihydroxyarylphosphine oxide mixtures as prepared in accordancewith Example 2, the glycidyl ethers thus prepared are treated with oneor more of the pure hydroxyarylphosphine oxides of Example 1 or thedihydroxyarylphosphine oxide mixtures of Example 2 to form various epoxyresins of this invention.

EXAMPLE 6 Epoxy Laminate

[0148] To a 32 oz glass jar 211 g (100 phr) of epoxy resin solids,prepared as described in Example 3a, 5.67 g (2.7 phr) dicyandiamide, 0.1g 2-methylimidazole (0.05 phr), and 35 g dimethylformamide (17 phr) wasadded and stirred vigorously for 15 min and then allowed to sit at 25°C. for 24 hours. Several plies of glass cloth (12 in², 7628 style) wereindividually coated with the above varnish. The impregnated sheets werethen held into a laboratory oven at a temperature of 170° C. for 3minutes to form the prepregs. Then eight of the prepreg plies werestacked together with two sheets of copper foil on either side andpressed together in a hydraulic press for 1.2 hours at 205° C. toproduce a consolidated laminate.

[0149] Following the procedures of Example 6 and employing the variousother epoxy resins of Examples 3, 4 or 5, various other epoxy laminatesof this invention are prepared.

EXAMPLE 7 Epoxy Laminate Comparisons.

[0150] This Example 7 demonstrates the flame-retardant activity ofvarious phosphine oxide mixtures of the present invention. In thisExample 7, a series of laminates was prepared using a few of thepreferred embodiments of the invention as described hereinabove. Theepoxy laminates were prepared following the procedures as set forth inExample 6. The laminates so formed were tested for their T_(g), forthermal properties according to TGA, for combustibility according to UL94, and time taken to delaminate at 260° C. according to the T-260 test.Table 3 summarizes these thermomechanical properties of variouslaminates formed in accordance with the procedures of Example 6 andemploying the phosphine oxides formed in accordance with Examples 3a,3c, 3d and 3e. TABLE 3 Comparison of Bis(4-hydroxyphenyl)phenylphosphineOxide Mixture/ EPON 828 Adduct Using Different Ratios of MixtureComponents. Patent TGA UL 94^(b) Example Components^(a) Tg (5% T₁, t₂T-260^(c) Resin (phr) % P (TMA) loss) (sec) (minutes) 3a Resin 100 1.8146 372 55, 0 >18 (mixture) DICY 2.7 2MI 0.05 3c Resin 100 1.9 143 37475, 0 >19 (pure bis) DICY 2.8 2MI 0.05 3d Resin 100 1.9 144 372 34,0 >19 (high tris) DICY 2.4 2MI 0.035 3e Resin 100 1.9 137 369 52, 0 >19(high mono) DICY 3.2 2MI 0.9

[0151] According to prior art (JP 186186A), the purebis(4-hydroxyphenyl)-phenylphosphine oxide displayed flame retardantproperties when used with a novolak epoxy resin system, giving a V-0 inthe UL-94 test. The Table 3 data in this study compares the relativeflame retardant activity of the corresponding mixture material with thepure bis compound using a simple formulation based on the bisphenol Adiglycidyl ether, which is known to be more difficult to flame-retard.Noteworthy observations are that higher levels of the trishydroxy didnot impact the T_(g), but a higher level of monohydroxy does. Themixtures demonstrated improved inherent flame retardant properties vs.the pure bis material, as evidenced by the self-extinguishing nature inthe UL-94 test and the relative burn times. The mixture is comparable tothe pure bis with regards to the T_(g). High thermal stability isapparent as evidenced by the high values obtained in the TGA and T-260analyses.

[0152] Although the invention has been illustrated by certain of thepreceding examples, it is not to be construed as being limited thereby;but rather, the invention encompasses the generic area as hereinbeforedisclosed. Various modifications and embodiments can be made withoutdeparting from the spirit and scope thereof.

What is claimed is:
 1. A mixture of hydroxyarylphosphine oxidescomprising: (a) a mono(hydroxyaryl)phosphine oxide of the formula:

wherein R₁ is a divalent, substituted or unsubstituted arylene moietyand R₂ is a monovalent, substituted or unsubstituted aryl moiety or isan alkyl moiety or is an aralkyl moiety; and (b) abis(hydroxyaryl)phosphine oxide of the formula:

wherein R₁ and R₂ are defined as above; and (c) atris(hydroxyaryl)phosphine oxide of the formula:

wherein R₁ is defined as above; and (d) optionally containing minoramounts of a pentavalent phosphine oxide of the formula:

wherein R₂ is defined as above.
 2. The mixture according to claim 1,wherein R₁ is derived from an alkyl aryl ether.
 3. The mixture accordingto claim 1, consisting essentially of diphenyl(4-hydroxyphenyl)phosphineoxide, bis(4-hydroxyphenyl)phenylphosphine oxide andtris(4-hydroxyphenyl)phosphine oxide, said mixture optionally includingminor amounts of triphenylphosphine oxide.
 4. The mixture according toclaim 1, consisting essentially ofbis(4-methylphenyl)(4-hydroxyphenyl)phosphine oxide,bis(4-hydroxyphenyl)(4-methylphenyl)phosphine oxide andtris(4-hydroxyphenyl)phosphine oxide, said mixture optionally includingminor amounts of tris(4-methylphenyl)phosphine oxide.
 5. The mixtureaccording to claim 1, consisting essentially ofbis(1-naphthyl)(4-hydroxyphenyl)phosphine oxide,bis(4-hydroxyphenyl)(1-naphthyl)phosphine oxide andtris(4-hydroxyphenyl)phosphine oxide, said mixture optionally includingminor amounts of tris(l-naphthyl)phosphine oxide.
 6. The mixtureaccording to claim 1, consisting essentially ofbis(2-naphthyl)(4-hydroxyphenyl)phosphine oxide,bis(4-hydroxyphenyl)(2-naphthyl)phosphine oxide andtris(4-hydroxyphenyl)phosphine oxide, said mixture optionally includingminor amounts of tris(2-naphthyl)phosphine oxide.
 7. The mixtureaccording to claim 1, consisting essentially ofbis(4-phenoxyphenyl)(4-hydroxyphenyl)phosphine oxide,bis(4-hydroxyphenyl)(4-phenoxyphenyl)phosphine oxide andtris(4-hydroxyphenyl)phosphine oxide, said mixture optionally includingminor amounts of tris(4-phenoxyphenyl)phosphine oxide.
 8. The mixtureaccording to claim 1, consisting essentially ofbis(2,4,5-trimethylphenyl)(4-hydroxyphenyl)phosphine oxide,bis(4-hydroxyphenyl)(2,4,5-trimethylphenyl)phosphine oxide andtris(4-hydroxyphenyl)phosphine oxide, said mixture optionally includingminor amounts of tris(2,4,5-trimethylphenyl)phosphine oxide.
 9. Themixture according to claim 1, consisting essentially ofbis(tert-butyl)(4-hydroxyphenyl)phosphine oxide,bis(4-hydroxyphenyl)(tert-butyl)phosphine oxide andtris(4-hydroxyphenyl)phosphine oxide, said mixture optionally includingminor amounts of tris(tert-butyl)phosphine oxide.
 10. The mixtureaccording to claim 1, wherein said mixture comprises from about 10 toabout 50 mole percent of the mono(hydroxyaryl)phosphine oxide of theformula (I), from about 30 to about 60 mole percent of thebis(hydroxyaryl)phosphine oxide of the formula (II), from about 10 to 50mole percent of the tris(hydroxyaryl)phosphine oxide of the formula(III) and from about 0 up to about 10 mole percent of the pentavalentphosphine oxide of the formula (IV).
 11. A mixture ofglycidoxyarylphosphine oxides comprising: (a) amono(glycidoxyaryl)phosphine oxide of the formula:

wherein R₁ is a divalent, substituted or unsubstituted arylene moietyand R₂ is a monovalent, substituted or unsubstituted aryl moiety or isan alkyl moiety or is an aralkyl moiety; and (b) abis(glycidoxyaryl)phosphine oxide of the formula:

wherein R₁ and R₂ are defined as above; and (c) atris(glycidoxyaryl)phosphine oxide of the formula:

wherein R₁ is defined as above; and (d) optionally containing minoramounts of a pentavalent phosphine oxide of the formula:

wherein R₂ is defmed as above.
 12. The mixture according to claim 11,consisting essentially of diphenyl(4-glycidoxyphenyl)phosphine oxide,bis(4-glycidoxyphenyl)phenylphosphine oxide andtris(4-glycidoxyphenyl)phosphine oxide, said mixture optionallyincluding minor amounts of triphenylphosphine oxide.
 13. The mixtureaccording to claim 11, consisting essentially ofbis(4-methylphenyl)(4-glycidoxyphenyl)phosphine oxide,bis(4-glycidoxyphenyl)(4-methylphenyl)phosphine oxide andtris(4-glycidoxyphenyl)phosphine oxide, said mixture optionallyincluding minor amounts of tris(4-methylphenyl)phosphine oxide.
 14. Themixture according to claim 11, consisting essentially ofbis(1-naphthyl)(4-glycidoxyphenyl)phosphine oxide,bis(4-glycidoxyphenyl)(1-naphthyl)phosphine oxide andtris(4-glycidoxyphenyl)phosphine oxide, said mixture optionallyincluding minor amounts of tris(I -naphthyl)phosphine oxide.
 15. Themixture according to claim 11, consisting essentially ofbis(2-naphthyl)(4-glycidoxyphenyl)phosphine oxide,bis(4-glycidoxyphenyl)(2-naphthyl)phosphine oxide andtris(4-glycidoxyphenyl)phosphine oxide, said mixture optionallyincluding minor amounts of tris(2-naphthyl)phosphine oxide.
 16. Themixture according to claim 11, consisting essentially ofbis(4-phenoxyphenyl)(4-glycidoxyphenyl)phosphine oxide,bis(4-glycidoxyphenyl)(4-phenoxyphenyl)phosphine oxide andtris(4-glycidoxyphenyl)phosphine oxide, said mixture optionallyincluding minor amounts of tris(4-phenoxyphenyl)phosphine oxide.
 17. Themixture according to claim 11, consisting essentially ofbis(2,4,5-trimethylphenyl)(4-glycidoxyphenyl)phosphine oxide,bis(4-glycidoxyphenyl)(2,4,5-trimethylphenyl)phosphine oxide andtris(4-glycidoxyphenyl)phosphine oxide, said mixture optionallyincluding minor amounts of tris(2,4,5-trimethylphenyl)phosphine oxide.18. The mixture according to claim 11, consisting essentially ofbis(tert-butyl)(4-glycidoxyphenyl)phosphine oxide,bis(4-glycidoxyphenyl)(tert-butyl)phosphine oxide andtris(4-glycidoxyphenyl)phosphine oxide, said mixture optionallyincluding minor amounts of tris(tert-butyl)phosphine oxide.
 19. Themixture according to claim 11, wherein said mixture comprises from about10 to about 50 mole percent of the mono(glycidoxyaryl)phosphine oxidederived from the phosphine oxide of the formula (I), from about 30 toabout 60 mole percent of the bis(glycidoxyaryl)phosphine oxide derivedfrom the phosphine oxide of the formula (II), from about 10 to 50 molepercent of the tris(glycidoxyaryl)phosphine oxide derived from thephosphine oxide of the formula (III) and from about 0 up to about 10mole percent of the pentavalent phosphine oxide of the formula (IV). 20.An epoxy oligomeric product derived from a mixture ofhydroxyarylphosphine oxides by way of reacting said mixture ofhydroxyarylphosphine oxides with epichlorohydrin, said mixture ofhydroxyarylphosphine oxides comprising: (a) a mono(hydroxyaryl)phosphineoxide of the formula:

wherein R₁ is a divalent, substituted or unsubstituted arylene moietyand R₂ is a monovalent, substituted or unsubstituted aryl moiety or isan alkyl moiety or is an aralkyl moiety; and (b) abis(hydroxyaryl)phosphine oxide of the formula:

wherein R₁ and R₂ are defined as above; and (c) atris(hydroxyaryl)phosphine oxide of the formula:

wherein R₁ is defined as above; and (d) optionally containing minoramounts of a pentavalent phosphine oxide of the formula:

wherein R₂ is defined as above.
 21. A flame retardant epoxy compositionderived from a mixture of hydroxyarylphosphine oxides by way of reactingsaid mixture of hydroxyarylphosphine oxides with an epoxy resincomposition, said mixture of hydroxyarylphosphine oxides comprising: (a)a mono(hydroxyaryl)phosphine oxide of the formula:

wherein R₁ is a divalent, substituted or unsubstituted arylene moietyand R₂ is a monovalent, substituted or unsubstituted aryl moiety or isan alkyl moiety or is an aralkyl moiety; and (b) abis(hydroxyaryl)phosphine oxide of the formula:

wherein R₁, R₂ are defined as above; and (c) atris(hydroxyaryl)phosphine oxide of the formula:

wherein R₁, is defined as above; and (d) optionally containing minoramounts of a pentavalent phosphine oxide of the formula:

wherein R₂ is defined as above.
 22. The epoxy composition according toclaim 21, further comprising a curing agent and optionally including afiller and a diluent.
 23. The epoxy composition according to claim 22,wherein said curing agent is selected from the group consisting ofanhydrides, amines, amides, Lewis acids, and phenolic based novolakresins.
 24. The epoxy composition according to claim 22, wherein saiddiluent is a glycidyl ether.
 25. A resin-impregnated compositecomprising a reinforcing component and the flame retardant epoxycomposition according to claim 21, at least partially cured.
 26. Theresin-impregnated composite according to claim 25, including a glassfiller, a glass fiber or a glass fabric.
 27. The resin-impregnatedcomposite according to claim 26, wherein said composite includes a glassfabric.
 28. A laminate, optionally including a copper foil layer adheredto the resin-impregnated composite of claim
 25. 29. A laminate,optionally including a copper foil layer adhered to theresin-impregnated composite of claim
 26. 30. A laminate, optionallyincluding a copper foil layer adhered to the resin-impregnated compositeof claim
 27. 31. The laminate according to claim 30, wherein saidlaminate includes a plurality of layers of resin-impregnated glassfabric, press-formed into a substantially integrated structure generallyinseparable into its constituent layers.
 32. A flame retardant curablecomposition comprising at least one component selected from the groupconsisting of: (i) an epoxy component derived from a mixture ofhydroxyarylphosphine oxides by way of reacting said mixture ofhydroxyarylphosphine oxides with a diglycidyl ether or mixture ofdiglycidyl ethers or polyglycidyl ethers; and (ii) a mixture of glycidylethers derived from said mixture of hydroxyarylphosphine oxides, saidmixture of hydroxyarylphosphine oxides comprising: (a) amono(hydroxyaryl)phosphine oxide of the formula:

wherein R₁ is a divalent, substituted or unsubstituted arylene moietyand R₂ is a monovalent, substituted or unsubstituted aryl moiety or isan alkyl moiety or is an aralkyl moiety; and (b) abis(hydroxyaryl)phosphine oxide of the formula:

wherein R₁ and R₂ are defined as above; and (c) atris(hydroxyaryl)phosphine oxide of the formula:

wherein R₁ is defined as above; and (d) optionally containing minoramounts of a pentavalent phosphine oxide of the formula:

wherein R₂ is defined as above.
 33. The curable composition according toclaim 32, further comprising an epoxy resin based on epichlorohydrin andbisphenol A, bisphenol F, or a novolak epoxy resin.
 34. The curablecomposition according to claim 32, wherein at least one component is anoligomer derived from the reaction of said mixture ofhydroxyarylphosphine oxides with a mixture of glycidyl ethers derivedfrom said mixture of hydroxyarylphosphine oxides.
 35. The curablecomposition according to claim 32, further comprising a curing agent andoptionally including a filler and a diluent.
 36. The curable compositionaccording to claim 35, wherein said curing agent is selected from thegroup consisting of anhydrides, amines, amides, Lewis acids, andphenolic based novolak resins.
 37. The curable composition according toclaim 35, wherein said diluent is a glycidyl ether.
 38. Aresin-impregnated composite comprising a reinforcing component and theflame retardant curable composition according to claim 32, at leastpartially cured.
 39. The resin-impregnated composite according to claim38, including a glass filler, a glass fiber or a glass fabric.
 40. Theresin-impregnated composite according to claim 39, wherein saidcomposite includes a glass fabric.
 41. A laminate, optionally includinga copper foil layer adhered to the resin-impregnated composite of claim38.
 42. A laminate, optionally including a copper foil layer adhered tothe resin-impregnated composite of claim
 39. 43. A laminate, optionallyincluding a copper foil layer adhered to the resin-impregnated compositeof claim
 40. 44. The laminate according to claim 43, wherein saidlaminate includes a plurality of layers of resin-impregnated glassfabric, press-formed into a substantially integrated structure generallyinseparable into its constituent layers.
 45. A flame retardant curableepoxy composition derived from a mixture of hydroxyarylphosphine oxidesby way of reaction with an epoxy novolak composition or a bisphenol A orbisphenol F derived epoxy composition, said mixture ofhydroxyarylphosphine oxides comprising. (a) a mono(hydroxyaryl)phosphineoxide of the formula:

wherein R₁ is a divalent, substituted or unsubstituted arylene moietyand R₂ is a monovalent, substituted or unsubstituted aryl moiety or isan alkyl moiety or is an aralkyl moiety; and (b) abis(hydroxyaryl)phosphine oxide of the formula:

wherein R₁ and R₂ are defined as above; and (c) atris(hydroxyaryl)phosphine oxide of the formula:

wherein R₁ is defined as above; and (d) optionally containing minoramounts of a pentavalent phosphine oxide of the formula:

wherein R₂ is defined as above.
 46. The epoxy composition according toclaim 45, further comprising a curing agent and optionally including afiller and a diluent.
 47. The epoxy composition according to claim 46,wherein said curing agent is selected from the group consisting ofanhydrides, amines, amides, Lewis acids, and phenolic based novolakresins.
 48. The epoxy composition according to claim 46 wherein saiddiluent is a glycidyl ether.
 49. A resin-impregnated compositecomprising a reinforcing component and the flame retardant epoxycomposition according to claim 45, at least partially cured.
 50. Theresin-impregnated composite according to claim 49, including a glassfiller, a glass fiber or a glass fabric.
 51. The resin-impregnatedcomposite according to claim 50, wherein said composite includes a glassfabric.
 52. A laminate, optionally including a copper foil layer adheredto the resin-impregnated composite of claim
 49. 53. A laminate,optionally including a copper foil layer adhered to theresin-impregnated composite of claim
 50. 54. A laminate, optionallyincluding a copper foil layer adhered to the resin-impregnated compositeof claim
 51. 55. The laminate according to claim 54, wherein saidlaminate includes a plurality of layers of resin-impregnated glassfabric, press-formed into a substantially integrated structure generallyinseparable into its constituent layers.
 56. A method of making amixture of hydroxyarylphosphine oxides comprising: (a) preparing a mixedGrignard reaction mixture including the species (RI)MgX and (R₂)MgXwherein R₁ is an arylalkylether radical and R₂ is an aryl or alkyl oraralkyl radical, X representing a halogen atom; (b) reacting said mixedGrignard reaction mixture with phosphorous oxychloride to produce amixture of arylalkyletherphosphine oxides; and (c) converting saidmixture of arylalkyletherphosphine oxides to a mixture ofhydroxyarylphosphine oxides, wherein said mixture ofhydroxyarylphosphine oxides includes: (i) a mono(hydroxyaryl)phosphineoxide of the formula:

wherein R₁ is a divalent, substituted or unsubstituted arylene moietyand R₂ is a monovalent, substituted or unsubstituted aryl moiety or isan alkyl moiety or is an aralkyl moiety; and (ii) abis(hydroxyaryl)phosphine oxide of the formula:

wherein R₁ and R₂ are defined as above; and (iii) atris(hydroxyaryl)phosphine oxide of the formula:

wherein R₁ is defined as above; and (iv) optionally containing minoramounts of a pentavalent phosphine oxide of the formula:

wherein R₂ is defined as above.
 57. A method of making a mixture ofhydroxyarylphosphine oxides comprising: (a) preparing a Grignard reagentincluding the species (R₁)MgX wherein R₁ is an arylalkylether radical, Xrepresenting a halogen atom; (b) preparing a Grignard reagent includingthe species (R₂)MgX wherein R₂ is an aryl or alkyl or aralkyl radical, Xis defined as above; (c) reacting said Grignard reagent (R₂)MgX withphosphorus oxychloride; (d) after reaction of said Grignard reagent(R₂)MgX with phosphorous oxychloride, adding said Grignard reagent(RI)MgX so as to produce a mixture of arylalkyletherphosphine oxides;and (e) converting said mixture of arylalkyletherphosphine oxides to amixture of hydroxyarylphosphine oxides, wherein said mixture ofhydroxyarylphosphine oxides includes: (i) a mono(hydroxyaryl)phosphineoxide of the formula:

wherein R₁ is a divalent, substituted or unsubstituted arylene moietyand R₂ is a monovalent, substituted or unsubstituted aryl moiety or isan alkyl moiety or is an aralkyl moiety; and (ii) abis(hydroxyaryl)phosphine oxide of the formula:

wherein R₁ and R₂ are defined as above; and (iii) atris(hydroxyaryl)phosphine oxide of the formula:

wherein R₁ is defined as above; and (iv) optionally containing minoramounts of a pentavalent phosphine oxide of the formula:

wherein R₂ is defined as above.
 58. The method according to claim 56,wherein said step of converting said mixture of arylalkyletherphosphineoxides to said mixture of hydroxyarylphosphine oxides includes treatingsaid mixture with a mineral acid selected from the group consisting ofHBr, HI and HCl in the presence of a metal halide salt.
 59. The methodaccording to claim 57, wherein said step of converting said mixture ofarylalkyletherphosphine oxides to said mixture of hydroxyarylphosphineoxides includes treating said mixture with a mineral acid selected fromthe group consisting of HBr, HI and HCl in the presence of a metalhalide salt.
 60. A bis(hydroxyphenyl)phosphine oxide of the formula:

wherein −R is selected from the group consisting of


61. The bis(hydroxyphenyl)phosphine oxide according to claim 60, havingthe structural formula:


62. The bis(hydroxyphenyl)phosphine oxide according to claim 60, havingthe structural formula:


63. The bis(hydroxyphenyl)phosphine oxide according to claim 60, havingthe structural formula:


64. The bis(hydroxyphenyl)phosphine oxide according to claim 60, havingthe structural formula:


65. The bis(hydroxyphenyl)phosphine oxide according to claim 60, havingthe structural formula:


66. The bis(hydroxyphenyl)phosphine oxide according to claim 60, havingthe structural formula:


67. A diglycidyl ether of the formula:

wherein n is an integer from 0 to 100 and wherein −R is selected fromthe group consisting of


68. The diglycidyl ether according to claim 67 wherein n is an integerfrom 0 to
 20. 69. The diglycidyl ether according to claim 67 wherein nis an integer from 0 to
 5. 70. The diglycidyl ether according to claim67 wherein −R is


71. The diglycidyl ether according to claim 67 wherein −R is


72. The diglycidyl ether according to 67 wherein −R is


73. The diglycidyl ether according to claim 67 wherein −R is


74. The diglycidyl ether according to claim 67 wherein −R is


75. The diglycidyl ether according to claim 67 wherein −R is


76. An epoxy composition derived from a bis(hydroxyphenyl)phosphineoxide of the formula:

wherein −R is selected from the group consisting of

by way of reaction with an epoxy resin.
 77. The epoxy compositionaccording to claim 76 wherein −R is


78. The epoxy composition according to claim 76 wherein −R is


79. The epoxy composition according to claim 76 wherein −R is


80. The epoxy composition according to claim 76 wherein −R is


81. The epoxy composition according to claim 76 wherein −R is


82. The epoxy composition according to claim 76 wherein −R is


83. The epoxy composition according to claim 76 wherein −R is


84. The epoxy composition according to claim 76 wherein the epoxy resinis derived from bisphenol A.
 85. The epoxy composition according toclaim 76 wherein the epoxy resin is derived from bisphenol F.
 86. Theepoxy composition according to claim 76 wherein the epoxy resin is epoxynovolak resin.
 87. A flame retardant epoxy composition comprising theepoxy composition of claim 76, a curing agent and optionally including afiller and a diluent.
 88. The flame retardant epoxy compositionaccording to claim 87, wherein said curing agent is selected from thegroup consisting of anhydrides, amines, amides, Lewis acids, andphenolic based novolak resins.
 89. The flame retardant epoxy compositionaccording to claim 87, wherein said diluent comprises a glycidyl ether.90. A resin-impregnated composite comprising reinforcing component andthe flame retardant epoxy composition according to claim 76, at leastpartially cured.
 91. The resin-impregnated composite according to claim90, including a glass filler, a glass fiber or a glass fabric.
 92. Theresin-impregnated composite according to claim 91, wherein saidcomposite includes a glass fabric.
 93. A laminate, optionally includinga copper foil layer adhered to the resin-impregnated composite of claim90.
 94. A laminate, optionally including a copper foil layer adhered tothe resin-impregnated composite of claim
 91. 95. A laminate, optionallyincluding a copper foil layer adhered to the resin-impregnated compositeof claim
 92. 96. The laminate according to claim 95, wherein saidlaminate includes a plurality of layers of resin-impregnated glassfabric, press-formed into a substantially integrated structure generallyinseparable into its constituent layers.
 97. A curable epoxy compositionincluding a component derived from a bis(hydroxyphenyl)phosphine oxideof the formula:

wherein −R is selected from the group consisting of

by way of reaction with: (i) epichlorohydrin or (ii) a diglycidyl etheror polyglycidyl ether, optionally including a diglycidyl ether ofbisphenol A or a diglycidyl ether of the formula:

wherein n is an integer from 0-to 100, and R is defined as above, or(iii) a mixture of glycidyl ethers derived from a mixture ofhydroxyarylphosphine oxides, said mixture of hydroxyarylphosphine oxidescomprising: (a) a mono(hydroxyaryl)phosphine oxide of the formula:

wherein R₁ is a divalent, substituted or unsubstituted arylene moietyand R₂ is a monovalent, substituted or unsubstituted aryl moiety or isan alkyl moiety or is an aralkyl moiety; and (b) abis(hydroxyaryl)phosphine oxide of the formula:

wherein R₁ and R₂ are defined as above; and (c) atris(hydroxyaryl)phosphine oxide of the formula:

wherein R₁ is defined as above; and (d) optionally containing minoramounts of a pentavalent phosphine oxide of the formula:

wherein R₂ is defined as above, optionally including an additional epoxyresin component.
 98. The curable epoxy composition according to claim 97wherein n is an integer from 0 to
 20. 99. The curable epoxy compositionaccording to claim 97 wherein n is an integer from 0 to
 5. 100. Thecurable epoxy composition according to claim 97 which is derived fromthe reaction of said bis(hydroxyphenyl)phosphine oxide with diglycidylether of bisphenol A or bisphenol F or an epoxy novolak resin.
 101. Thecurable epoxy composition according to claim 97 including a componentwhich is derived from the reaction of said bis(hydroxyphenyl)phosphineoxide with diglycidyl ether of the formula:

wherein n and R are defined as above.
 102. The curable epoxy compositionaccording to claim 97 including a component which is derived from thereaction of said bis(hydroxyphenyl)phosphine oxide with a mixture ofglycidyl ethers derived from a mixture of hydroxyarylphosphine oxides byway of reacting said mixture of hydroxyarylphosphine oxides withepichlorohydrin, said mixture of hydroxyarylphosphine oxides comprising:(a) mono(hydroxyaryl)phosphine oxide of the formula:

wherein R₁ is a divalent, substituted or unsubstituted arylene moietyand R₂ is a monovalent, substituted or unsubstituted aryl moiety or isan alkyl moiety or is an aralkyl moiety; and (b) abis(hydroxyaryl)phosphine oxide of the formula:

wherein R₁ and R₂ are defined as above; and (c) atris(hydroxyaryl)phosphine oxide of the formula:

wherein R₁ is defined as above; and (d) optionally containing minoramounts of a pentavalent phosphine oxide of the formula:

wherein R₂ is defmed as above.
 103. A flame retardant epoxy compositioncomprising the curable epoxy composition of claim 97, a curing agent andoptionally including a filler and diluent.
 104. The flame retardantepoxy composition according to claim 103, wherein said curing agent isselected from the group consisting of anhydrides, amines, amides, Lewisacids, and phenolic based novolak resins.
 105. The flame retardant epoxycomposition according to claim 103, wherein said diluent comprises aglycidyl ether.
 106. A resin-impregnated composite comprising areinforcing component and the flame retardant epoxy compositionaccording to claim 103, at least partially cured.
 107. Theresin-impregnated composite according to claim 106, including a glassfiller, a glass fiber or a glass fabric.
 108. The resin-impregnatedcomposite according to claim 107, wherein said composite includes aglass fabric.
 109. A laminate, optionally including a copper foil layeradhered to the resin-impregnated composite of claim
 106. 110. Alaminate, optionally including a copper foil layer adhered to theresin-impregnated composite of claim
 107. 111. A laminate, optionallyincluding a copper foil layer adhered to the resin-impregnated compositeof claim
 108. 112. The laminate according to claim 111, wherein saidlaminate includes a plurality of layers of resin-impregnated glassfabric, press-formed into a substantially integrated structure generallyinseparable into its constituent layers.
 113. An epoxy compositionderived from a bis(hydroxyphenyl)phosphine oxide of the formula:

wherein −R is selected from the group consisting of

by way of reaction with an epoxy novolak resin or an epoxy resin ofepichlorohydrin and bisphenol A or bisphenol F.
 114. A flame retardantepoxy composition according to claim 113, further comprising a curingagent and optionally including a filler and diluent.
 115. The flameretardant epoxy composition according to claim 114, wherein said curingagent is selected from the group consisting of anhydrides, amines,amides, Lewis acids, and phenolic based novolak resins.
 116. The flameretardant epoxy composition according to claim 114, wherein said diluentcomprises a glycidyl ether.
 117. A resin-impregnated compositecomprising reinforcing component and the flame retardant epoxycomposition according to claim 114, at least partially cured.
 118. Theresin-impregnated composite according to claim 117, including a glassfiller, a glass fiber or a glass fabric.
 119. The resin-impregnatedcomposite according to claim 118, wherein said composite includes aglass fabric.
 120. A laminate, optionally including a copper foil layeradhered to the resin-impregnated composite of claim
 117. 121. Alaminate, optionally including a copper foil layer adhered to theresin-impregnated composite of claim
 118. 122. A laminate, optionallyincluding a copper foil layer adhered to the resin-impregnated compositeof claim
 119. 123. The laminate according to claim 122, wherein saidlaminate includes a plurality of layers of resin-impregnated glassfabric, press-formed into a substantially integrated structure generallyinseparable into its constituent layers.
 124. A triglycidyl ether of theformula:


125. A curable composition comprising: a) at least one component takenfrom the group of: (i) a tris(o-glycidoxyphenyl)phosphine oxidegenerally of the formula:

and (ii) a tris(p-glycidoxyphenyl)phosphine oxide generally of theformula:

b) optionally including a mixture of hydroxyarylphosphine oxidescomprising: (i) a mono(hydroxyaryl)phosphine oxide of the formula:

wherein R₁ is a divalent, substituted or unsubstituted arylene moietyand R₂ is a monovalent, substituted or unsubstituted aryl moiety or isan alkyl moiety or is an aralkyl moiety; and (ii) abis(hydroxyaryl)phosphine oxide of the formula:

wherein R₁ and R₂ are defined as above; and (iiii) atris(hydroxyaryl)phosphine oxide of the formula:

wherein R₁ is defined as above; and (iv) optionally containing minoramounts of a pentavalent phosphine oxide of the formula:

wherein R₂ is defined as above; and c) at least one additional curableepoxy resin component optionally including epoxy resins derived fromepichlorohydrin and hydroxyaryl compounds such as bisphenol A, Novolakresins, epoxy cresol-Novolak resins and mixtures thereof.
 126. A flameretardant epoxy composition comprising the curable composition of claim125, a curing agent and optionally including a filler and a diluent.127. The flame retardant epoxy composition according to claim 126,wherein said curing agent is selected from the group consisting ofanhydrides, amines, amides, Lewis acids, and phenolic based novolakresins.
 128. The flame retardant epoxy composition according to claim126, wherein said diluent comprises a glycidyl ether.
 129. Aresin-impregnated composite comprising a reinforcing component and thecurable composition according to claim 125, at least partially cured.130. The resin-impregnated composite according to claim 129, including aglass filler, a glass fiber or a glass fabric.
 131. Theresin-impregnated composite according to claim 130, wherein saicomposite includes a glass fabric.
 132. A laminate, optionally includinga copper foil layer adhered to the resin-impregnated composite of claim129.
 133. A laminate, optionally including a copper foil layer adheredto the resin-impregnated composite of claim
 130. 134. A laminate,optionally including a copper foil layer adhered to theresin-impregnated composite of claim
 131. 135. The laminate according toclaim 134, wherein said laminate includes a plurality of layers ofresin-impregnated glass fabric, press-formed into a substantiallyintegrated structure generally inseparable into its constituent layers.136. A mixture of alkoxyarylphosphine oxides comprising: (a) amono(alkoxyaryl)phosphine oxide of the formula:

wherein R₁ is a divalent, substituted or unsubstituted arylene moiety;R₂ is a monovalent, substituted or unsubstituted aryl moiety or is analkyl moiety or is an aralkyl moiety and R₃ is a C₁-C₆ aliphaticradical; and (b) a bis(alkoxyaryl)phosphine oxide of the formula:

wherein R₁, R₂ and R₃ are defined as above; and (c) atris(alkoxyaryl)phosphine oxide of the formula:

wherein R₁ and R₃ are defined as above; and (d) optionally containingminor amounts of a pentavalent phosphine oxide of the formula:

wherein R₂ is defined as above.